I managed to get connected with the following.

Thanks

#include <M5Stack.h>

HardwareSerial Serial2(2);

int period = 158000;
unsigned long time_now = 0;

String cmd_DEF = "AT+FDEFAULT";
String cmd_OTTA_mode = "AT+MODE=LWOTAA";
String cmd_DevEui = "AT+ID=DevEui";
String cmd_JOIN = "AT+JOIN=FORCE";
String cmd_send_data = "AT+MSG="Data to send"";

void setup() {

M5.begin();
Wire.begin();
// Lcd display
M5.Lcd.setBrightness(100);
M5.Lcd.fillScreen(BLACK);
M5.Lcd.setCursor(10, 10);
M5.Lcd.setTextColor(WHITE);
M5.Lcd.setTextSize(1);
M5.Lcd.printf("LoraWAN Network");
delay(300);
M5.Lcd.fillScreen(BLACK);
delay(150);
M5.Lcd.setCursor(0, 10);
M5.Lcd.fillScreen(BLACK);
for(int i=0; i<200; i++) {
M5.Lcd.setBrightness(i);
delay(2);
}

Serial.begin(115200);

Serial2.begin(9600, SERIAL_8N1, 16, 17);
Serial2.flush();
/* LoRaWAN Init */
M5.Lcd.println("Setting up the LoraWAN Connetion");
Serial2.println(cmd_DEF);
delay(2000);
Serial2.println(cmd_OTTA_mode);
delay(1000);
Serial2.println(cmd_DevEui);
delay(1000);
Serial2.println(cmd_OTTA_mode);
delay(3000);
M5.Lcd.println("Joining Network.");
Serial2.println(cmd_JOIN);
delay(3000);
M5.Lcd.println("Message will be send in 155000ms, when next Band is availible");
}

void loop() {
if(millis() > time_now + period){
time_now = millis();
M5.Lcd.println("Sending Data.");
Serial2.println(cmd_send_data);
}
if(Serial2.available()) {
int ch = Serial2.read();
Serial.write(ch);
}
}